This Luchita's location is the original one, and I think still the best. Usually full, so make a reservation if you can (sometimes they take them, sometimes they don't). Otherwise you'll have to wait in a usually long line for a table. The bar will usually be packed on Saturday nights too, with people waiting for tables.
The food is the highlight here - the decor is nice, but you'll forget all about it once you get your dinner. Have a margarita or a beer and dig in. Personal favorites: the moles and the chili rellenos.
In short, authentic Mexican good in a better than average styled restaurant. More cozy and darker than your average loud, bright colors with sombreros on the walls type of thing.